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The Precautionary and Prohibited Medications Database

Maintained by a collaboration of the University at Buffalo Pharmacology Specialty Laboratory and Frontier Science & Technology Research Foundation

Medications Efavirenz and Medroxyprogesterone
Designation Precautionary
Last updated 24-Apr-2019
Interaction History
Effect on concentration Efavirenz: Unknown

Medroxyprogesterone: Decrease
Pharmacologic effect Efavirenz: N/A

Medroxyprogesterone: N/A
Pharmacologic effect applies to drugs in the same class Efavirenz:

Pharmacologic effect description Efavirenz:

Potential pharmacokinetic effect Efavirenz: N/A

Medroxyprogesterone: N/A
Potential pharmacokinetic effect applies to drugs in the same class Efavirenz:

Potential pharmacokinetic mechanism Efavirenz:



HIV patients on EFV-based HIV therapy were found to have lower progesterone levels in women on DMPA injections as a form of contraceptive. A more frequent dosing interval for the DMPA injection should be considered in these patients and caution should be exercised.


Efavirenz versus Depot medroxyprogesterone acetate

Study Design
This was a multicenter, single arm, study among women (n = 42) in sub-Saharan Africa stable on Efavirenz (EFV)-based antiretroviral therapy (ART) and Rifampicin (RIF)-based TB treatment. Plasma medroxyprogesterone acetate (MPA) concentrations were determined pre-dose and 2, 4,6, 8, 10 and 12 weeks after Depot medroxyprogesterone acetate (DMPA) 150 mg injection and measured plasma progesterone levels from week 2 onwards. The primary outcome measure was the proportion of women with sub-therapeutic MPA levels (<0.1 ng/mL) at week 12. MPA PK parameters were calculated using non-compartmental methods and compared with historical ART-na´ve controls without TB who received DMPA.  
Study Results
Five women [11.9% (95% CI 4.0-25.6%)] had MPA <0.1 ng/mL at week 12 with one of the five having MPA <0.1 ng/ml at week 10 compared to one of 16 (6,3%) at week 12 among the historical controls. No participant had progesterone levels >5 ng/mL (suggesting ovulation) throughout the study including at week 12. Compared to historical controls, median area under the concentration-time curve over 12 weeks (AUC0-12) was lower (7.63 vs. 12.38 ng*wk/mL, p=0.004) and apparent clearance was higher (19,681 vs. 12,117 L/ wk, p=0.004).  
Study Conclusions
MPA clearance was higher than in controls, leading to sub-therapeutic concentrations of MPA in some women at 10 and 12 weeks post-dose, though progesterone levels typically associated with ovulation were not observed. It may be prudent to dose DMPA more frequently than every 12 weeks in women on EFV.  
Mngqibisa, R, Cohn, SE, Kendall, MA, et al. Potential concern for timing of dmpa injection among women treated for hiv and tb. Conference On Retroviruses And Opportunistic Infections. Seattle . ; March 2019. 

Study information updated: 24-Apr-2019